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Full text of "IS 15501: Gaseous Fire Extinguishing Systems--IG 541 Extinguishing Systems"

**************** 




Disclosure to Promote the Right To Information 

Whereas the Parliament of India has set out to provide a practical regime of right to 
information for citizens to secure access to information under the control of public authorities, 
in order to promote transparency and accountability in the working of every public authority, 
and whereas the attached publication of the Bureau of Indian Standards is of particular interest 
to the public, particularly disadvantaged communities and those engaged in the pursuit of 
education and knowledge, the attached public safety standard is made available to promote the 
timely dissemination of this information in an accurate manner to the public. 




Mazdoor Kisan Shakti Sangathan 
"The Right to Information, The Right to Live'' 



IS 15501 (2004, Reaffirmed 2010) : Gaseous Fire 
Extinguishing Systems--IG 541 Extinguishing Systems. ICS 
13.220.10 




Jawaharlal Nehru 
'Step Out From the Old to the New" 



aj^&vi iJii^s:y%K^ isb^^ni^seg 



:<>5&i| mT'5K^5?::5:^>^i»l 



K^^^iXSVCd^ 



Satyanarayan Gangaram Pitroda 
Invent a New India Using Knowledge 



Bhartrhari — Nitisatakam 
''Knowledge is such a treasure which cannot be stolen" 




^'^^^r 



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IS15501 : 2004 

REAFFIRfilED 

M^ 3Tf^ ^FR Mc^fcliil - 3TTf^ 541 ^I^H ^^ 

Indian Standard 

GASEOUS FIRE EXTINGUISHING SYSTEMS — 
IG 541 EXTINGUISHING SYSTEMS 



ICS 13.220.10 



©BIS 2004 

BUREAU OF INDIAN STANDARDS 

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG 
NEW DELHI 110002 

August 2004 Price Group 7 



Fire Fighting Sectional Committee, CED 22 



FOREWORD 

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft fmalized by the Fire 
Fighting Sectional Committee had been approved by the Civil Engineering Division Council. 

The objective of this standard is to provide to the users of IG 541 systems with specific requirements for the 
control of fires of Class A or Class B type. It does not cover the design of explosion suppression systems. 

It is important that the fire protection of a building or plant be considered as a whole. IG 541 total flooding 
systems form only a part, though an important part, of the available fire protection facilities. It should not be 
assumed that the installation of an IG 541 total flooding system necessarily removes the need to consider 
supplementary measures, such as the provision of portable fire extinguishers or mobile appliances for first aid 
or emergency use, or measures to deal with special hazards. 

Controlled inert atmospheres are recognized as effective for extinguishing Class A and Class B fires where 
electrical risks are present. Nevertheless, it should not be forgotten, in the planning of comprehensive schemes, 
that there may be hazards for which this technique is not suitable, or that in certain circumstances or 
situations there may be danger in its use requiring special precautions. 



IS 15501 : 2004 



Indian Standard 

GASEOUS FIRE EXTINGUISHING SYSTEMS 
IG 541 EXTINGUISHING SYSTEMS 



1 SCOPE 

1.1 This standard sets out specific requirements for 
the design and installation of totalflooding fire 
extinguishing systems employing IG 541 gas 
extinguishant. This standard is applicable to single 
supply as well as distributed supply systems. 

1.2 This standard complements various general 
requirements applicable to all types of gaseous fire- 
extinguishing systems ( Halocarbon as well as Inert 
gas systems ) listed in IS 15493. As such, both 
these standards should be read together before 
designing a system. Where requirements in both 
the standards differ, this standard shall take 
precedence. 

1 .3 Before using IG 54 1 , nature of fire and fire spread 
shall be studied for suitability of extinguishment as 
high discharge time of 60 s may not be suitable for 
rapid spreading fires. 

1.4 This standard covers systems operating at 
nominal pressures of 1 5 MPa and 20 MPa only at 1 5°C. 

2 REFERENCES 

The standards given below contain provisions 
which through reference in this text, constitute 
provisions of this standard. At the time of publication, 
the editions indicated were valid. All standards are 
subject to revision, and parties to agreements based 
on this standard are encouraged to investigate the 
possibility of applying the most recent editions of the 
standards indicated below: 



IS No. 



7285:1988 



15493:2004 



Title 

Specification for seamless steel 
cylinders for permanent and high 
pressure liquefiable gases ( second 
revision ) 



Gaseous 
systems - 



fire extini^uishin» 



General requirements 

3 GENERAL INFORMATION 

3.1 Application 

Total flooding system is designed to develop a 
controlled atmosphere in an enclosed space yielding 
a reduced oxygen concentration, which will not 
sustain combustion. It is also designed to 



simultaneously increase carbon dioxide concentration 
to act as an automatic respiratory stimulant. This is 
achieved by increasing the carbon dioxide 
concentration from the normal atmospheric level of 
0.03 percent by volume to a concentration between 
2.5 percent and 5 percent. The appropriate IG 541 
concentration shall also be maintained until the 
temperature within the enclosure has fallen below the 
reignition point. 

3.2 The minimum concentration necessary to 
extinguish a flame and the minimum oxygen 
concentration necessary to support combustion have 
been determined by experiments for several surface- 
type fires particularly those involving liquids and 
gases. For deep-seated fires, longer soaking times 
may be necessary but are difficult to predict. 

3.3 It is important that residual carbon dioxide and 
oxygen concentrations are not only reached but also 
maintained for a sufficient period of time to allow 
effective emergency action by trained personnel. This 
is equally important in all classes offire since a persistent 
ignition source can lead to a recurrence of the initial 
event once this has dissipated. 

3.4 Before using iG 541 , nature offire and fire spread 
shall be studied for suitability of extinguishment as 
high discharge time of 60 s may not be suitable for 
rapid spreading fires. 

4 GAS CHARACTERISTICS AND PROPERTIES 

4.1 1G541 is a colourless, odourless and electrically 
non-conductive gas with a density approximately the 
same asthat of air. 

4.2 IG 54 1 gas is a mixture consisting normally of 52 
percent nitrogen, 40 percent argon and 8 percent 
carbon dioxide ( all by volume ). The mixture 
specification of IG 541 gas is shown in Table 1 . 

4.3 IG 541 system can be used for extinguishing 
fires of all classes within the limits specified 
in IS 15493. 

4.4 Components for IG 54 1 gas shall comply with the 
specification as shown in Table 2. 

4.5 Physical properties of IG 541 gas are shown in 
Table 3. 

4.6 Toxicological information for IG 541 gas is 
shown in Table 4. 



IS 15501 : 2004 



Table I Specirication for IG 541 Gas 

{Clause A 2) 



SI No. 

(1) 



ii) 

iii) 



Constituent 

(2) 
Carbon dioxide 
Argon 

Nitrogen 



Pcrcentiigc Range 

(3) 

7.6- 8.4 

37.2-42.8 

48.8-55.2 



Table 2 Specification for IG 541 

( Clause A A ) 



SI 

No. 

(0 

i) 



Spetifi- 
cution 

(2) 

Purity 



Argon 



(3) 



Nitrosicn 



(4) 



Carbon 
Dioxide 

(5) 



99.9 percent 99.9 percent 99.5 percent 



by volume, by volume, by volume, 

Min X'lin A4in 

ii) Moisture 4 x 10-^' by 5 x 10'^ by 10 x 10"^ by 

mass. McLX mass. Max mass, Max 

iii) Oxygen 3 x 10'^ by 3 x 10"^ by 10 x 10"^ 

mass, A/ax muss. Max oy mass, A-Zax 

Table 3 Physical Properties of IG 541 Gas 

{Clause 4.5) 

SI No. Property Value 

(1) (2) (3) 

i) Molecular mass 34 

ii) Boiling point at 0.1 MPa, ''C -196 

iii) Freezing point, °C -78.5 

iv) Vapour pressure at 20°C 15.2 

v) Specilic volume of superheated 0.697 
vapour at 100 kPa and 20°C 

Table 4 Toxicological Information for IG 541 Gas 

( Clause 4.6 ) 



Value, Percent 

(3) 
43 



SI No. Property 

(1) (2) 

i) No observed adverse effect 
level ( NOAEL ) 

ii) Lowest observed adverse effect 52 

level ( LOAHL ) 

NOTE — These values are the functional 
equivalents of NOAEL and LOAEL values which 
correspond to 12 percent minimum oxygen for the 
no-effect level and 10 percent minimum oxygen for 
the low-eiTect level. 

4.7 Fill Pressure 

The fill pressure of the IG 541 cylinder shall not 
exceed the values provided in Tables 5 and 6 
for systems operating at 15 MPa and 20 MPa 
respectively. 



Table 5 15 MPa Storage Container 
Characteristics for IG 541 

{Clause 4J) 



SI No, 



Property 



(1) 
i) 
ii) 



/a 1 u e 


MPa 


(3) 


15 


17.5 



(2) 

Pilling pressure 

Maximum container working 
pressure at 50°C 

NOTE — For further data on pressure/temperature 
relationship. I'lg. 1 should be referred. 

Table 6 20 MPa Storage Container 
Characteristics for IG 541 

{ Clause 4J) 



SI No. Property 

(1) (2) 

i) Filling pressure 

ii) Maximum container working 
pressure at 50°C 



Value 

MPa 

(3) 
20 

23.5 



5 SAFETY OF PERSONNEL 

In addition to the provisions specified under 
IS 15493, the following requirements shall also 
apply. 

5.1 Protection of Occupants 

IG 541 total flooding systems shall not be used in 
design concentrations greater than 52 percent 
( corresponds to injected concentrations of 
74 percent ) in normally occupied areas, unless 
means are provided to ensure safe egress of personnel 
prior to the discharge of the inert gas mixture. 

5.2 In areas, where there is a likelihood of significant 
difference between gross and net volumes of the 
enclosure, utmost care shall be exercised in proper 
system design. 

5.3 Though exposure to the concentration levels of 
oxygen and carbon dioxide (10 to 15 percent and 2.5 
to 5 percent by volume respectively) is normally 
considered to produce a negligible risk to the 
personnel, certain provisions like personnel training, 
warning signs, pre-discharge alarms, and discharge 
inhibit switch shall be put in place. In addition, adequate 
ventilation facilities shall be available to exhaust the 
trapped gases following extinguishment process. 

5.4 Safety limits and also minimum safety precautions 
that are associated with the use of IG 541 are as shown 
in Tables 7 and 8. Since a fire can be expected to 
consume oxygen and form decomposition products, 
personnel shall treat any tire situation as an emergency 
and promptly exit the enclosure. 



IS 15501 : 2004 



1 a 
























1 1 1 1 1 1 1 i 1 1 1 








§t> 
































MAXIMUM DEVELOPED PRESSURE — ^ 






y 


1 


































































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y 




1 
































































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1 






18 
























































/ 


/ 








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y 


1 










i 
























































y 




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1 






















































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X 














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Q_ 


































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2 




































A 




















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LU 
































/ 


X 






















1 










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^ 16 






























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r 
























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1 


































/ 




























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a: 
























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A 






























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*^ 


/' 






































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■ 


1 




















A 


t 


"N 






































1 










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i 


^ 








\ 


\_... 


































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y 


/ 












^^ REFERENCE TEMPERATURE 








1 










i 












y 


















































1 










1 






14 


r 


y 




















































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1 








T" 







10 



15 20 



30 



40 



50 



55 



60 65 70 



TEMPERATURE, X 
( NOTE : FILLING PESSURE 15 MPa 15^0 ) 



Fig. 1 Temperature/Pressure Variations for Inergen in Storage Containers 



5.5 Additional provisions as shown in Table 9 
shall apply to account for failure of safeguards 
( see 5.1 to 5.4 ) to prevent accidental exposures to 
the humans present within the enclosure. 

6 ENCLOSURE STRENGTH AND VENTING 
FACILITIES 

6.1 Venting shall be provided at levels as high as 
possible in the enclosure. Strength and allowable 
pressures for average enclosures may be in conformity 
with the following guidelines. The building 
requirements for the type of enclosure and free 
venting required can also be calculated from the 
relevant specifications. 

6.2 Free venting facilities shall be provided for the 
enclosure and the equation for the venting area required 
shall be as follows: 



where 
A 



/i-(5x 10-^)(2>P-o^) 



free venting area, in m-; 



Q = inergen agent discharge rate, in mVmin; 
and 

P = allowable strength of the enclosure, 
in kPa. 

NOTE— Value of /^ for various construction types 
is shown in Table 10. In case of exceptionally 
tight enclosures, the arrived value of A shall be 
multiplied by 3. 

7 EXTINGUISHING AGENT SUPPLY 
7.1 Quantity 

a) The amount of the IG 54 1 in the system shall 
be at least sufficient for the largest single 
hazard protected or group of communicating 
hazards that are to be protected 
simultaneously. 

b) Where required, the reserve quantity should 
be same as that of main supply as in 7.1(a). 
However if replenishing of 10 541 gas supply 
takes more than 7 days at the site of 



IS 15501 : 2004 



Table 7 Safety Precautions for IG 541 

(Clause 5.4) 



SI No. IG 541 Injected Concentration 

in Percent by Volume 

(1) (2) 

i) 43 percent (up to NOAEL) 

ii) 43 percent and 52 percent ( between 

the NOAEL and up to LOAEL ) 

iii) 52 percent ( above the LOAEL ) 





Requirements 




Inhibit Switch 


Egress in 30 s 


Safety 


Lock-off 


and Time Delay 


Max 


Interlock 


Valve 


(3) 


(4) 


(5) 


(6) 


V 


Not required 


Not required 


Not required 


V 


V 


V 


Not required 



V 



V 



V 



*Concentration levels above LOAEL are not permitted in occupied areas and question of egress does not arise. 

Table 8 Safety Limits for IG 541 

[Clauses5Aand7.32{Q)and{f)] 



SI No. 


Safety Limit 


IG 541 Design 
Concentration'^ 


Residual Oxygen 
Concentration^^ 


Residual Cai 

Dioxide 

Concentrati 


rbon 
on') 


IG 541 Injected 
Concentration'^ 


(1) 


(2) 




(3) 




(4) 






(5) 




(6) 


i) 


NOAEL 




43 




12 






3.5 




53 


ii) 


LOAEL 




52 




10 






4.2 




74 


iii) 


Carbon dioxide 




63 




7.8 






5.0 




98 


'^ Percentage by volume. 





















Table 9 Human Exposure to IG 541 Agent 

(Clause 5.5) 



SI No. 


Exposure 


IG 541 


Injected Agcn 


t Concentration 


(Percent) 




Up to 43 


Between 43 
and 52 


Between 52 
and 62 




More Than 
62 


(1) 


(2) 


(3) 


(4) 


(5) 




(6) 


i) 


Oxygen concentration ( percent ) in 
sea-level equivalent 


12 


Between 12 
and 10 


Between 10 
and 8 




Less than 
8 


ii) 


Status of space 


Normally 
Occupied 


Normally 
Occupied 


Normally 
unoccupied 




Normally 
unoccupied 


iii) 


Exposure time 


Not more 
than 5 min 


Not niore 
than 3 min 


No exposure 
permitted 




No exposure 
permitted 



Table 10 Allowable Strength of the Enclosure 

( Clause 6.2 ) 



SI No. 


Construction 


Type 


Typical Structures 


Allowable Load on Enclosure, kPa 


(1) 


(2) 




(3) 


(4) 


i) 


Light 




Lightweight partitions, glazing 


1.25 


ii) 


Normal 




Brick 


2.50 


iii) 


Vault 




Reinforced concrete 


5.00 



c) 



installation, advice may be sought from the 
authority concerned on the quantity to be 
kept available as reserve. 

Reserve supply where provided and the 
main supply should be permanently 
connected to the distribution piping and 



arranged for quick and easy changeover to 
enable uninterrupted protection. 

d) The quantity of IG 541 required shall be 
further adjusted to compensate for any 
special conditions, such as unclosable 
openings, forced ventilation, the free volume 



IS 15501 : 2004 



of air receivers that may discharge into the 
risk, altitude ( substantially above or below 
sea level ) or any other causes for the 
extinguishant loss. 

7.2 Total Flooding Quantity 

a) The amount of IG 541 required to achieve 
the design concentration shall be calculated 
from the following equations and this 
figure shall need further adjustment as stated 
in 7.1(d). 



M- 2.303 



X K, X Log 



100 



to]0 



S "" ^'^ 100-C 

where 

M = total flooding quantity, in kg; 

C = design concentration, percent by 
volume; 

K ^ net volume of the hazard, in m^; 

S = K^ ^ K^ (7), where K^ and K, are 
constants specific to the agent used 
and ris minimum temperature inside 
enclosure; and 

V^ = specific volume of superheated agent 
at2rC, inmVkg. 

Specific volume constants for IG 541 gas are 
/C, = 0.658 and K^ = 0.002 39. It may also be 
noted that this equation provides an allowance 
for the normal leakage from a tight enclosure. 

b) The agent requirement per unit volume of 
protected space can also be calculated by 
using the Table 11 for various levels of 
concentration corresponding to the 
temperature within the protected enclosure. 

NOTE — Quantity of the agent shall be the highest of 
the values calculated from the provisions contained 
in 7.2(a) and 7.2(b). 

7.3 The actual quantity of IG 541 gas storage 
required and the resultant residual oxygen and 
carbon dioxide concentrations produced shall be 
determined in the following manner, which shall 
further subject to changes for pressure change due 
to elevation (see 7.3.3). 

7.3.1 Enclosure Volumes 

The net enclosure volumes are calculated using the 
following equations: 

^ Max g s 

b) l-\,. - K, - V 

^ Mm Max o 

where 

^MiLv ^ maximum net volume of the 
enclosure, in m^; 



V = across volume of enclosure, in nr'; 

V^ ^ volume of the structural/similar 
permanent objects in the enclosure 
that gas can not permeate, in in'; 

Vj^jj^ == minimum net volume of enclosure 
considering the maximum anticipated 
volume of the occupancy related to 
the objects in the enclosure, in 
m''; and 

V == volume of the occupancy related 

objects in the enclosure that gas 
can not permeate, for example, 
furniture fittings, etc, in m'' ( This 
value may be ignored if the volume 
is less than 25 percent of the 
maximum net volume V^,^^ ). 

7.3.2 IG54I Parameters 

The required IG 541 gas quantity, number of 
cylinders, actual injected concentration, etc, are 
calculated using the following equations: 

a) IG 54 1 agent quantity ( Theoretical ) 

Hh = (''Max)(C,) (1) 

where 

A/^,^ = theoretical IG 541 quantity, in m^'; 

'^Max " maximum net volume of the 
enclosure, in m^; and 

Cj = appropriate injected concentration. 

b) IG 541 containers 

The number of containers required shall be 
as follows after rounding off as appropriate: 

N=MJM^ .,..(2) 

where 

A^ ~ number of containers 

A/,,j= theoretical IG 541 quantity, in m''; and 

yV/, ^ quantityofIG 541 agent per container, 
in m"*. 

Standard containers with standard filling 
pressures shall be adopted to facilitate 
logistics. 

c) Actual quantity of IG 541 agent 

The actual quantity of the agent is determined 
as per the equation below: 

M^-iNHM^) (3) 

where 

A/^= actual quantity of IG 541 storage, 
in m''; 

A^ == number of containers; and 

M^^ quantityofIG 541 agent per container, 
in ml 



IS 15501 : 2004 



Table 11 Total FloodingQuantity (IG 541) 

[Clause 7.2(b)] 



SI No. 


Temperature 
T 

X 


Specific 

Vapour 

Volume, S 

nvVkg 


IG 541 Mass 
Desi 


Requirements per Unit Volume of Protected Space 
( l^g/ni^ ) 
gn Concentration by Volume C ( Percent ) 




'34 


38 


42 


46 


50 


54 


58 


62 ^ 


(1) 


(2) 


(3) 


(4) 


(5) 


(6) 


(7) 


(8) 


(9) 


(10) 


(11) 


i) 


-~ 40 


0.562 4 


0.521 


0.600 


0.684 


0.773 


0.870 


0.975 


1.089 


1.214 


ii) 


- 35 


0.574 3 


0.511 


0.587 


0,669 


0.757 


0.852 


0.954 


1.066 


1.189 


iii) 


- 30 


0.586 3 


0.500 


0.575 


0.656 


0.742 


0.834 


0.935 


1.044 


1.165 


iv) 


- 25 


0.598 2 


0.490 


0.564 


0.643 


0.727 


0.818 


0.916 


1.023 


1.142 


V) 


-20 


0.610 2 


0.481 


0.553 


0.630 


0.713 


0.802 


0.898 


1.003 


1.119 


vi) 


™ 15 


0.622 1 


0.471 


0.542 


0.618 


0.699 


0.786 


0.881 


0.984 


1.098 


vii) 


-10 


0.634 1 


0,463 


0.532 


0.606 


0.686 


0.772 


0.864 


0.966 


1,077 


viii) 


- 5 


0.646 


0.454 


0.522 


0.595 


0.673 


0.757 


0.848 


0.948 


1.067 


ix) 





0.658 


0.446 


0.513 


0.584 


0.66! 


0.744 


0.833 


0.931 


1.038 


X) 


5 


0.669 9 


0.438 


0.504 


0.574 


0.649 


0.730 


0.818 


0.914 


1.019 


xi) 


10 


0.681 9 


0.430 


0.495 


0.564 


0.638 


0.717 


0.804 


0.898 


1.00! 


xii) 


15 


0.693 8 


0.423 


0.486 


0.554 


0.627 


0.705 


0.790 


0.882 


0.984 


xiii) 


20 


0.705 8 


0.416 


0.478 


0.545 


0.616 


0.693 


0.777 


0.868 


0.968 


xiv) 


25 


0.717 7 


0.409 


0.470 


0.536 


0.606 


0.682 


0.764 


0.853 


0,951 


XV) 


30 


0.729 7 


0.402 


0.462 


0.527 


0.596 


0.670 


0.751 


0.839 


0.936 


XV i) 


35 


0.741 6 


0.395 


0.455 


0.518 


0.586 


0.660 


0.739 


0.826 


0.921 


xvii) 


40 


0.753 6 


0.389 


0.448 


0.510 


0.577 


tf.649 


0.727 


0.812 


0.906 


xviii) 


45 


0.765 5 


0.383 


0.441 


0.502 


0.568 


0.639 


0.716 


0.800 


0.892 


xix) 


50 


0.777 5 


0.377 


0.434 


0.494 


0,559 


0.629 


0.705 


0.787 


0,878 


XX) 


55 


0.789 4 


0.371 


0.427 


0.487 


0.551 


0.620 


0.694 


0.776 


0.865 


xxi) 


60 


0.801 4 


0.366 


0.421 


0.480 


0.543 


0.610 


0.684 


0.764 


0.852 


xxii) 


65 


0.813 3 


0.361 


0.415 


0.473 


0.535 


0.601 


0.674 


0.753 


0.840 


xxiii) 


70 


0.825 3 


0.355 


0.409 


0.466 


0.527 


0.593 


0.664 


0.742 


0.827 


xxiv) 


75 


0.837 2 


0.350 


0.403 


0.459 


0.519 


0.584 


0.655 


0.731 


0.816 


xxv) 


80 


0.849 2 


0.345 


0.397 


0.453 


0.512 


0.576 


0.645 


0.721 


0.804 


xxvi) 


85 


0.861 1 


0.341 


0.392 


0.446 


0.505 


0.568 


0.636 


0.711 


0.793 


xxvii) 


90 


0.873 1 


0.336 


0.386 


0.440 


0.498 


0.560 


0.628 


0.701 


0.782 


xxviii) 


95 


0.885 


0.33! 


0.381 


0.434 


0.491 


0.553 


0.619 


0.692 


0.772 


xxix) 


100 


0.897 


0.327 


0.376 


0.429 


0.485 


0.545 


0.611 


0.683 


0.761 



d) Actua! IG 541 injected concentration 

The actual injected concentration of the agent 
based on the actual quantity of the IG 541 
agent storage is calculated as below: 

^^r^A^^M.. (4) 

where 



C 



A! 



M^ 



^ actual IG 541 injected concentration; 

= actual quantity of IG 541 storage, in 
m-\ and 

maximum net volume of the 
enclosure, in m-\ 

e) Concentration levels of oxygen (-) and CO^ 



Max 



( + ) for the injected concentration 

The reduced oxygen and increased CO2 
concentrations for the actually injected 
concentration of the IG 541 agent shall be 
established and the same shall be within the 
limits specified in Fig. 2. These limits contain 
the safety range for the occupied areas. The 
concentration levels shall also satisfy the 
safety limits contained in Table 8. 

Actual concentration level using the actua! 
quantity of 10 54 1 agent. Using the actual 
quantity of the IG 54 1 agent and actual injected 
concentration for the minimum net volume 



IS 15501 : 2004 



of the protected area, the concentration levels 
of oxygen and CO^ shall be established from 
reference to Fig. 2 and the same shall be within 
the safety range. Similarly, the concentration 
levels shall also satisfy the safety limits 
contained in Table 8. 

g) Lastly, it is required to adjust the number of 
IG 541 agent containers, where necessary, by 
compensating for ambient pressure change 
due to location elevation as per 7.3.3 and 
round off the number as before. The equation 
in such cases will be as follows: 

tV, = A^times atmospheric correction factor, 

A^^ = adjusted number of containers, and 

A^ ^ initial number of containers. 

7.3.3 Atmospheric Correction Factors 

It shall be necessary to adjust the actual IG 541 agent 
quantity for altitude effects. Depending upon the 
altitude, atmospheric correction factor shall be applied 
as per the Table 12. The adjusted IG 541 agent quantity 
is determined by multiplying the number of IG 541 
containers by the ratio of average ambient enclosure 
pressure to standard sea level pressure. 

8 CONCENTRATION REQUIREMENTS 

8.1 Fire Extinguishing Concentration 

a) The minimum design concentration of the 
IG 54 1 agent, for Class A surface fire hazards 
shall be the extinguishing concentration 
with a loading of 20 percent as a safety factor 
( 36.5 percent). 

b) The minimum design concentration of the 
IG 54 1 agent for Class B fuel hazards shall 
be the extinguishing concentration with a 
loading of 30 percent as a safety factor. 

c) Combustible solids — The minimum injected 
concentration of IG 54 1 agent for surface type 
Class A risks shall not be less than 40 percent 
by volume which yields, on a free efflux basis, 
a residual oxygen concentration of 14 percent 
by volume in the enclosure. 

NOTE — For combination of hazards and fuels 
in one enclosure, the fire extinguishing shall be the 
value for the fuel/hazard requiring the highest 
concentration. 

d) Oxygen concentration — The oxygen 
percentages, below which no mixture is 
flammable are to be guided by values given 
in Table 1 3 where the mixture is a flammable 
gas or vapour with air, using either nitrogen 
or carbon dioxide as a dilutant ( components 
oflG541). 

e) Carbon dioxide concentration — The 
IG 54 1 injected concentration for all classes 



of risk shall be such as to yield a residual 
CO^ concentration in normally occupied 
enclosures of between 2.5 and 4.5 percent 
by volume. 

9 APPLICATION RATE AND DISCHARGE 
TIME 

9.1 Rate of Application 

The design application rate shall be based on the 
quantity of IG 541 ( A/^ ) as per 7.3.2 for the desired 
concentration ( as per 8.1 or 8.2 as the case may be ) 
and for the time allotted to achieve the design 
concentration as per 9.2. The oxygen and CO^ 
concentrations, however, shall be within the limits as 
specified in 5.3. 

9.2 Duration of IG 541 Discharge 

a) The discharge time period is defined as the 
time required to discharge from the nozzles 
95 percent of the agent mass at 2 1 ^C, necessary 
to achieve the minimum design concentration 
based on required safety factor for flame 
extinguishment. 

b) The minimum theoretical injected design 
concentration shall be achieved within I min 
and the actual injected concentration ( that 
is the above plus a suitable safety factor, 
adjustment for container rounding off ) shall 
be achieved within 2 min. 95 percent of the 
minimum design quantity of the agent shall 
be released within 60 s. 

c) Flow calculations performed in accordance 
with 13 or in accordance with the approved 
pre-engineered systems, shall be us'ed to 
demonstrate the discharge time requirements 
stated above. 

d) When an extended discharge is desired to 
maintain the design concentration for the 
specified period of time, additional quantities 
ofagent can be applied at a reduced rate. The 
initial discharge shall be completed within 
the limits as specified above. Performance 
of the extended discharge shall be 
demonstrated by test. 

e) Where containers are situated remote from 
the protected enclosure, extended agent 
transit time will be apparent. Authorities 
concerned shall be consulted before locating 
the containers in such cases. 

9.3 Retention Time 

Following the discharge of the agent into the 
enclosure, at least 80 percent of the design 
concentration ( or inerting concentration as the case 
may be ) shall remain within the enclosure, when 
measured after 1 min of dischari^e. 







22 


CO 






o 




20 


1- 






< 

a: 




18 


1- 








111 


16 


O 


^ 




o 


3 


14 


o 


o 




III 


> 




Q 


> 


12 


X 


CO 




o 


LU 




Q 


< 


10 


^ 


1- 




O 


2 


8 


(Tl 


LU 




cr: 


O 




< 


q: 


6 


() 


LU 


Q 


a. 




Z 




4 


< 






Z 






LU 




'^ 


O 






> 






X 






o 





















































































'^ 


^ 






















































INtKUtIN D^ -4U-bd 






"^ 


















































































"^ 




..^ 




r- 


1 ^ 










































































coD^^/^tyj 




































































L^^^A?r^ oW_ ' 


































































7-/oXr^^A/ 
































































■ 


1 " ^'t//?i;?H 


L^ 












































1 T 1 1 1 1 1 1 1 1 1 1 

OXYGEN CONCENTRATION 12 6 


% RY Vni 1 IMF^ 












































p^ 














































... .. 










::: 












































































"^ 




-^ 


-^ 






































. 














































-- 
































EXAMPLE 
















































-— 






















































































































RESIDUAL CARBON DIOXIDE 




















































CONCENTRA" 


HON CURVE -7 






















.^ ' 




















































/ 










































































— 


J. 


i 






■ 


CAKbUFN UigAlUt UUrNUbN 1 KA 


nOlN 6.^ 7o bY VULUMb 




__^_ 





L— 




1 — 


*— — 
















































- 




— - 


— 




^ 


















































-— ^ 




U— 




1 




























































—- 


■^ 


-^ 







































































10 20 30 40 50 60 70 80 

ACTUAL INERGEN INJECTED CONCENTRATION (Cia). PERCENTAGE BY VOLUME 

Fig. 2 Predicted Oxygen and Carbon Dioxide Residual Concentration Curves ( Based on Free Efflux ) 



m 

o 



O 



IS 15501 : 2004 



Table 12 Atmospheric Correction Factors 

{Clausel33) 



SI No. 


Equiva 


[lent Altiti 


ide, m 


El 


nclos 


lire 


Pressure, 


mm 


IlK 


Ati 


mosphei 


ric Correction Factor 


(0 




(2) 










(3) 










(4) 


i) 




-920 










840 










1.11 


ii) 




-610 










812 










1.07 


iii) 




-300 










787 










1.04 


iv) 















760 










1,00 


V) 




300 










733 










0.96 


vi) 




610 










705 










0.93 


vii) 




920 










678 










0.89 


viii) 




1 220 










650 










0.86 


ix) 




1 520 










622 










0.82 


X) 




1 830 










596 










0.78 


xi) 




2 130 










570 










0,75 


xii) 




2 440 










550 










0.72 


xiii) 




2 740 










528 










0.69 


xiv) 




3 050 










505 










0.66 



Table 13 Fire Extinguishing Concentrations 

[Clause ^A{A)] 



Gas or Vapour 



(1) 
Inorganic 
Hydrogen 
Carbon monoxide 
Hydrocarbons 
Methane 
Ethane 
Propane 
Butane 
Isobutane 
Pentane 
Hexane 
Ethylene 
Propylene 
Butene 
Butadiene 
Benzene 
Cyclopropane 

Alcohols 
Methyl alcohol 

Ketones 
Acetone 

Miscellaneous 
Coal gas 

Gasoline 



Oxygen Concentration, Percent 



With Nitrogen as 
Dilutant of Air 

(2) 



5.0 
5.6 

12.1 
II.O 
1L4 
12.1 
12.0 
12.1 
11.9 
10.0 
11.5 
11.6 
10.4 
11.2 
11.7 

10.3 

1 3.5 

11.5 
11.6 



With Carbon Dioxide 
as Dilutant of Air 

(3) 

5.9 
5.9 

14.6 
13.4 
14.3 
14.5 
14.8 
14.4 
14.5 
1 1.7 
14.1 
14.0 
13.1 
13.9 
13.9 

13.5 

15.6 

14.4 
14.4 



IS 15501 : 2004 



10 POST DISCHARGE REQUIREMENTS 

a) After 2 min from the commencement of 
discharge, the situation shall be as under: 



1) 



Carbon dioxide — Residual 
concentration shall be between 
2.5 percent to 5 percent by volume and 
shall be within 0.5 percent by volume of 
the predicted concentration. 

Under no circumstances, the 
concentration shall be below 
2.5 percent or more than 4.5 percent by 
volume. 



2) Oxygen — Residual concentration shall 
be within 5 percent of the value derived 
from Fig. 3 corresponding to the actual 
injected concentration of Inergen. 

The concentrations shall be measured 
at not more than 1 m from the floor and 
at 75 percent of the height of the enclosure 
or at the top of the highest hazard to be 
protected. 

3) After 1 min from the commencement of 
discharge, the situation shall be as under: 



Carbon dioxide concentration shall be 
between 2.5 percent and 4.5 percent by 
volume. The residual oxygen 
concentration shall be not greater than 
1 .2 times the predicted residual oxygen 
concentration. 

11 STORAGE CONTAINERS 

The Inergen storage containers shall comply with the 
following in addition to various requirements contained 
in IS 15493: 

a) The containers used in IG 541 systems 
shall be seamless cylinders conforming to 
IS 7285 designed, fabricated, inspected, 
certified and stamped in accordance with the 
requirements of Chief Controller of Explosives, 
Nagpur. 

b) The design pressure shall be suitable for the 
maximum pressure developed at 55°C or at 
the maximum controlled temperature limit. 

c) The storage containers shall have reliable 
means of ind icating their pressure. 

d) The storage containers shall have reliable 
means of indicatini? the variation of container 



z 

o 

< 

cr 

g! 

O : 
Z 

o 
o 

UJ 

9 

X 

o 



O uJ 
GQ O 

< LLt 



< 

Q 

(/) 
UJ 

a: 



— POSSIBLE DANGER TO LIFE 



NOAEL 
UPPER O2 LIMIT 
FOR OCCUPIED 
AREAS (53% Ci) 



NOAEL 
UPPERO LIMIT 
FOR OCCUPIED 
AREAS (74% Ci) 



UPPER CO2 LIMIT FOR 
RESPIRATION CONTROL 



CO2 CONTENT IN EXPIRED 
BREATH 



UPPER O2 
LIMIT FOR 
EXTINGUISHING 

(34%Ci) 



LOWER CO2 LIMIT FOR 
RESPIRATION CONTROL 



I I I 




OXYGEN 

CONTENT IN 

ATMOSPHERE 



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 
RESIDUAL OXYGEN CONCENTRATION. PERCENTAGE BY VOLUME 

* PREDICTED OXYGEN AND CARBON DIOXIDE RESIDUAL 
CONCENTRATIONS FOR NOAEL AND LOAEL 

Fig. 3 Acceptablf, Range of RriSiouAL Oxygen and Cakiu)n Dioxidi-: Concentration 

i-oR Occupied Areas 



10 



IS 15501 : 2004 



pressure with temperature. A pressure/ 
temperature chart attached to the container, 
is acceptable. 

e) The requirements of authorities having 
jurisdiction for containers may take 
precedence over the requirements of this 
standard, if their specifications are more 
stringent. 

12 DISTRIBUTION SYSTEM 

The Inergen distribution system shall comply with 
the following in addition to various requirements 
contained in IS 15493. 

12.1 Piping Network 

a) The piping shall withstand the maximum 
expected pressure at the maximum storage 
temperature, as follows: 

1) 15 MPa system — 22.5 MPa at 55X 

2) 20 MPa system — 30 MPa at 55^C 

b) The piping shall withstand the maximum 
developed pressure at 55°C and shall be in 
accordance with IS 1 5493. 

c) Carbon steel pipes and fittings shall be 
galvanized inside and outside or otherwise 
suitably protected against corrosion. 
Stainless steel pipes and fittings may be used 
without corrosion protection. 

12.2 Piping Fittings 

a) Pipe fittings shall comply with the 
requirements given in IS 15493. 

b) Fittings shall be selected according to the 
wall thickness or schedule number of the pipe 
to which they are intended to be fitted. 

12.3 Pipe Sizing 

Pipe sizing is a complex issue, particularly when too 
small a bore results in excessive pressure losses while 
too large a bore reduces the flow velocity. This also 
may result in excess pressure drops and lower flow 
rates. Table 14 may be used as a guide to estimate 
pipe sizes. The sizes can be checked using an approved 
computer flow calculation programme. 

12.4 Nozzle Placement 

a) The type of nozzles selected, their number 
and placement shall be such that the design 
concentration will be established in all parts 
of the protected enclosure and such that the 
discharge will not unduly splash flammable 
liquids or create dust clouds that could extend 
the fire, create an explosion, or otherwise 
adversely affect the contents or the integrity 



Table 14 Pipe Size Chart 

(Clause 12.3) 



SI No, Fine Size Maximum I !o>v Rate, mVmin 



m m Short Run Long Run 

(Up to 6 m) (Above 6 ni 

and Up to 30 ni) 



(1) 


(2) 


(3) 


(4) 


i) 


6 


5 


1.0 


ii) 


10 


8 


1.5 


iii) 


12 


15 


3.0 


iv) 


20 


30 


5.5 


V) 


25 


50 


10.0 


vi) 


32 


100 


18.0 


vii) 


40 


140 


25.0 


viii) 


50 


250 


45.0 


ix) 


63 


350 


65.0 


>:) 


80 


600 


100.0 


xi) 


100 


1 100 


200.0 


xii) 


125 


1 800 


300.0 


xiii) 


150 


2 800 


500.0 


xiv) 


200 


5 000 


900.0 



of the enclosure. 

b) Nozzles shall be selected and located to 
protect an area less than its area of coverage. 
The area of coverage to the type of nozzle 
shall be so listed for the purpose. 

c) Maximum nozzle height above floor level for 
a single row of nozzles is 3.5 m. Where ceiling 
height ( of the protected enclosure ) exceeds 
3.5 m, an additional row of nozzles shall be 
provided for uniform and faster distribution 
of the agent within the enclosure. 

d) Minimum nozzle height above the floor level 
of the hazard shall be 0.2 m. 

e) In case of enclosures having no false ceiling, 
nozzles can be located on the ceiling 
anywhere within 0.5 m to 5 m from the walls 
In case of enclosures having false ceilings, 
deflector shields shall be used with each 
nozzle and also nozzles shall be so located 
( with an anticipation of dislodgement of false 
ceiling materials or any movable objects in 
the path of discharge ) to prevent any damage 
thereto. 

f) Nozzles shall be provided in all the concealed 
spaces, floor voids, ceiling voids, etc, besides 
the main area within the protected enclosure. 

g) Selecting the number of nozzles in a system 
shall take into account, the shape of the 
enclosure ( area and volume ), shape of the 
void ( raised floor, suspended ceiling ). 



IS 15501 :2004 



Installed equipment in the enclosure/void 
( Chimney effect ), allowed pressure at the 
restrictor ( pipe quality ), obstructions, which 
may affect the distribution of the discharged 
agent and architectural considerations. 

h) In hazards having suspended ceiling, 
consideration shall be given for having 
nozzles installed in the ceiling void 
( simultaneous discharge ) in order to 
equalize the pressure during discharge, thus 
reducing the risk of unnecessary damaging 
ceiling tiles etc. 

j) In hazards having raised floor ( not gas 
tight ) consideration shall be given for 
having nozzles installed in the floor void 
( simultaneously discharge ) in order to 
equalize the pressure and obtain 
extinguishing concentration below the 
floor. 

k) In hazards having suspended ceiling, 
nozzles for protecting rooms void shall be 
installed in such a way that the jets from 
.the nozzles do not damage the ceiling 
plated excessively during discharge, that is, 
the nozzles to be positioned vertically with 
the discharge holes free of the ceiling tiles 
and/or Escutcheon plates. For light weight 
ceiling tiles, it may be recommended to 
securely anchor tiles for a minimum of 1.5 m 
from each discharge nozzle. 

m) The maximum distance between nozzles 
should not exceed 6 m and the maximum 
distance to wall/partition should not exceed 
3 m. 

13 HYDRAULICS OF THE SYSTEM 

13.1 An approved hydraulic calculation method shall 
be employed to predict pipe sizes, nozzle pressure, 
agent flow rate, discharge per nozzle and the discharge 
time. 

13.2 The various parameters described in 7.3.1,7.3.2, 
9.1 and 9.2 shall be considered to determine the 
following minimum limits of accuracy: 

a) The weight of agent predicted by flow 
calculation to discharge from the nozzle 
should agree with the total weight of agent 
actually discharged from each nozzle in the 
system within a range of -5 percent to +10 
percent of actual prediction. 

b) The discharge time predicted by the flow 
calculation method should agree with the 
actual discharge time from each nozzle in the 
system within a range of ± 5 s. 



c) The accuracy of the calculated nozzle 
pressures versus actual pressures at each 
nozzle should be such that actual nozzle 
pressures in an installation will not fatl outside 
the range required for acceptable nozzle 
performance. 

14 COMMISSIONING AND ACCEPTANCE 
TESTING 

14.1 Criteria for Acceptance 

The completed IG 54 1 total flooding system shall be 
commissioned in accordance with IS 15493 and the 
system's performance proved by at least one of the 
following methods: 

a) It is not normally recommended to conduct 
full-scale discharge test of IG 541 total flooding 
systems. Where the authorities concerned 
insist on full-scale discharge test, the tests 
shall be conducted in accordance with 15. 

b) Where a full discharge test using IG 541 is 
not insisted by the authorities concerned, 
the following procedures shall apply: 

1) Subject the distribution system to a 
hydrostatic pressure test of 1.50 times 
the calculated pipework's maximum 
developed storage pressure at 55°C, then 
purge the system to remove moisture and 
prove free passage. 

2) Subject the protected area to an 
enclosure integrity test in accordance 
IS 15493. 

14.2 Commissioning Certification 

When the system commissioning is completed 
the installation agency shall issue a typical test 
certificate. 

14.3 Where the system fails to comply with various 
provisions as stated above, the fault shall be rectified 
and, if necessary, the system retested. 

15 IG 541 FULL SCALE DISCHARGE TEST 
PROCEDURE 

15.1 This shall be in accordance with IS 15493. 

15.2 Recommissioning 

Restore all systems to a fully operational status. 

15.3 Reporting 

The following shall be reported: 

a) Information identifying the system shall 
include; 



12 



IS 15501 : 2004 

1) Installation, designer and contractor; c) Discharge time. 

2) Enclosure identifications; j) Concentration levels at each sampling point 

3) Enclosure temperature prior to discharge; at 2 min and 1 min from the commencement 

4) Oxygen and carbon dioxide residual ^^ discharge, 
concentrations; and ^^ ^^^^^^ deficiencies. 

5) Position of sampling points. 

Q Referenceto this test method in accordance 

b) Date and time of test. ^1^1^ jg 13493 



13